Techniques according to the related art, for use in observing the surface of a magnetic material, include the Bitter technique, the Kerr microscopy, the spin-polarized scanning electron microscopy (hereinafter referred to as SPIN-SEM), the Lorentz electron microscopy, the magnetic force microscopy (MFM: Magnetic Force Microscopy), and so forth. The Bitter technique is a long-established technology whereby a colloidal solution of magnetic particulates is dropped on the surface of a magnetic specimen to thereby observe a pattern of the magnetic particulates attracted to the vicinity of a magnetic domain wall of the specimen by use of an optical microscope. The Kerr microscopy is a magneto-optic technique for observing a magnetic domain with the use of a polarization microscope by making use of the magnetic Kerr effect whereby upon linearly polarized light falling on a magnetic specimen, resultant reflected light is turned into elliptically polarized light, the technique as well having been known for a long time. The SPIN-SEM microscopy is a technique whereby a spin of a secondary electron emitted upon irradiation of a magnetic material with an electron beam is decomposed into three-dimensional spectral components to thereby detect the spin {refer, to for example, Jpn. J. Appl. Phys., by K. Koike, et al., Vol. 24, L542 (1985)}. The secondary electron emitted from the magnetic material has information on spin magnetic moment inside the specimen, and if the information can be detected to be mapped, both the magnitude, and the orientation of magnetization on the surface of the specimen can be obtained as a two-dimensional image. The Lorentz electron microscopy is a technique for visualizing a magnetic domain wall, or a magnetic domain by utilizing a bend of an electron beam, caused by a Lorentz force that the electron beam has received from inside the specimen upon the electron beam transmitting through a magnetic material.
On the other hand, the magnetic force microscopy (MFM) is based on a technique called the atomic force microscopy (AFM: Atomic Force Microscopy) without use of light and an electron beam. This technique is a technique for mapping a magnetic force distribution by scanning the surface of a specimen with a probe while detecting a magnetic force acting between a cantilever having the probe with a magnetic matter coated thereon and a magnetic specimen, as deflection of the cantilever {refer to, for example, Appl. Phys. Lett., by Y. Martin et al., Vol. 50, 1455 (1987)}. As an atomic force besides a magnetic force and so forth are acting on the probe, it is necessary to separate the magnetic force from other interaction. Accordingly, the cantilever is first vibrated, and a distance between the probe and the specimen is adjusted such that a decrease in vibration amplitude, due to the atomic force acting at the time of contact between the probe and the specimen, is held constant. By so doing, a position of the surface of the specimen, in the direction of height, is decided upon, and with the probe kept in its state away from the surface of the specimen by a given distance from the position, the magnetic force acting at a long distance is detected from a phase change in vibration of the cantilever.